1. BERSON, F. A. 1950: On the factors controlling the instability of long waves in Zonal currents. Arkiv f. Geof., K. Vetenskapsakad., I, 9 Stockholm. (See also Summary, 1949, Tellus, I, 4, pp. 44-52.)
2. ON THE THEORY OF CYCLONES
3. HELMHOLTZ, H., 5858. Ober die Integrak der hydro-dynamischen Gleichungen welche den Wirbelbe-wegungen entsprechen. Ges. Abh., p. lol, Crelle.